Is there any utility I can use to make Poser 4 textures work on Poser 3 figures or Ultramorph woman ? I managed to paste a P4 t-shirt texture onto the P3 casual woman but doing this for a whole figure would be more complicated.

In theory, you could use UVmapper to remap the Poser 3 figures to match the Poser 4 mapping. This would not be a beginner's project (!) although lots of Poser 3 users would thank you for it :-) If it's body textures you want, there are still P3 maps available at Strike a Pose: http://www.spaceports.com/~helend/Textures/index.html and at Winscape 2010: http://www.fortunecity.com/tatooine/darkknight/369/index.htm

If you're good in Photoshop, it's simple enough to rebuild a P4 texture to fit a P3 figure. I've done that several times, and the results are always remarkable when you think what a P3 looks like. Check my gallery for Backstage 13, and you'll see what happened when Lawboy got moved into the new century. Very different from the original model, and all it took was a new skin texture and a new hair prop.

I'v got a P3 NudFem remapped for P4 here.